On a day like this, there is only one thing I can say to someone like you who is a dear friend through and through, and that is to wish the happiest birthday to you!
May you enjoy your special day to the fullest, best friend!
Forgetfulness is one of the many symptoms of ageing, my friend.
I know your memory is starting to play tricks on you, but you shouldn’t worry, I will always be your best friend. I’ll be around long after you've forgotten who I am.
I’ve never met someone as young at heart as you. You are the coolest and youngest adult I know and, if anything, you are the one who makes me feel old. Your joy never ends.
May you continue to grow younger while others grow old!